Each 1m2 of ClearVue windows is currently rated to generate about 30 Wp of electric power, tested and confirmed by one of the world’s leading technical service organisations TÜV SÜD in China, using windows of size 1.44 m2. The energy produced by windows depends on the installation location, system orientation, tilt angles, system design and implementation, seasons and weather, etc.

Per day

The approximate formula for a skylight or a tilted roof-mounted window facing towards equator is simple: Daily Power = 30 Wp/m2 * (Number of m2) * (Number of peak sunshine hours for the location). In Perth, 10 North-facing roof-mounted windows of total area 10 m2 will produce approximately 30W/m2*10m2*4.5h = 1350 Wh = 1.35 kWh of electric energy daily.

A very close result is obtained by using open source solar data and online calculator published by the National Renewable Energy Laboratory (NREL, USA) at pvwatts.nrel.gov which produces 1.38kWh accounting for a 14% system loss.

At Warwick Grove test installation, the daily averaged energy production is near 1.6 kWh, generated by approx. 25 m2 of windows installed in 4 different sections of the structure. Due to the effect of non-optimum angles, and some strong shading, the averaged energy production figure is close to 70 Wh/m2/day.

It should also be noted that these energy production figures have been measured after the battery storage losses (around 10%), and the DC-to-AC conversion losses (min. 10-15%), thus showing only the approx. 75-80% of the actual energy generated by the solar windows. In future, larger-scale installations of solar windows will run at reduced rates of electric power loss, be placed in different optimum orientations not placed in a shaded environment.

Per year

In Perth, Western Australia with approx. 300 sunny days and 65 cloudy/rainy days per annum, we evaluated that approx. 605 kWh will get generated annually by the 18 active PV windows installed at Warwick Grove. The measured data accumulated over the period between May 2019 – May 2020 shows that we generated approx. 500 kWh/year, as measured from the storage system, and past all electric losses. Given that the estimated electric losses were min. 20%, this solar windows installation is currently running according to the predicted parameters.

For a summer sunny-day generation in excess of 1720 Wh (stored available energy), the energy production during the cloudy rainy days is typically seen at 900-1300 Wh per day. During much shorter winter days, we still store up to 1200-1300 Wh of energy daily.

The Warwick installation (approx. 25 m2) if it were all optimally oriented (on a North-facing non-shaded roof section), would have generated 1142 kWh per annum, as calculated using the same online NREL Calculator. This figure corresponds to the daily average of 3.12 kWh versus the current daily average near 1.37 kWh/day from the less than optimally oriented current configuration.

How much energy do ClearVue windows make?

A realistic estimate based on actual measured performance at Warwick Grove predicts generating approx. 70 kWh/day from each 1000 m2 of ClearVue windows installed. Annually, in excess of 20 MWh from each 1000 m2 of ClearVue windows in climates like Perth’s.

With one panel?

One window of even 0.5m2 size will generate enough energy to operate an electrochromic-type (or polymer dispersed liquid crystal (PDLC)) transparency control layer integrated into the window. It can also power the window-integrated roller blinds system, or many LED lights mounted around the window perimeter. Daily average generation of ~ 135 Wh (orientation dependent) from a 1m2 window is sufficient for fully charging more than 13 mobile phone batteries (at about 8-10 Wh each). 100 Wh = 0.1 kWh.

The average total daily electricity consumption of a 3-bedroom household in Australia is about 15 kWh. If you were to use 20 suitably mounted ClearVue windows installed into unshaded pergola roof areas you could expect to offset approx. 18% of daily electricity consumption, due to generating approx. 2.71 kWh daily. As an example, a roof-mounted 6.6kWp mono-Si PV system offsets around 60% of the electricity bill in Perth, Western Australia. However, the roof based PV does not itself save on HVAC demand requirements – the ClearVue PV windows do. Find out more about our energy savings here. 100 Wh of energy is required to operate a 100W-rated incandescent light bulb for 1 hour (or ten (10 x ) 10W (approx 450-500 lumen) LED lights bulbs for 1 hour)

With one floor of a building?

1 floor of an office building can have around 200 windows of size 3.2m x 1.2m installed. We use the window sizes reported in one of the Company’s video presentations, to make an example. Then, the predicted energy generation is approx. = 60.5 kWh. This energy is sufficient for powering 242 lamps of rated power consumption 25W each, for 10 hours each day.

With one side of a building?

Considering 10 floors containing up to 200-300 large-area windows each, generating up to 1 MWh/day is possible. Provided that the building side orientation is selected to be close to the direction optimised for the local geography/climate.

With a whole building?

Since various window orientations may be involved, it is best to contact the ClearVue team for a feasibility analysis. Request a Feasibility Study for your project now.

The most important parameter characterising the PV module performance is Specific Yield (SY), measured in kWh/kWp, and showing the annual produced energy (in kWh) per each 1 kWp (1000 Wp) of installed generation capacity.

Typical values of SY for optimally mounted roof-based silicon PV are between 1300-1500 kWh/kWp.

A conservative estimate for the SY of Warwick Grove trial installation can be made using the predicted annual generation: 605 kWh / (30Wp*18) = 1120 kWh/kWp. Installations of ClearVue solar windows on optimally oriented tilted roofs will have SY values exceeding these of conventional PV.

For conventional (silicon modules-based) rooftop PV installations in Perth, Australia, average daily energy generation outputs of about 4.4 kWh/kWp have been reported, meaning that a 2kWp roof-based PV system can potentially generate about 8.8 kWh of electric energy daily (if optimally tilted & oriented). A 2kWp ClearVue installation can potentially generate approximately the same daily energy, requiring approx. 50 smaller windows of size 1.3m2 each (even if largely non optimally oriented & tilted, such as a building façade).

1m2 at 22% efficiency (silicon) roof-based PV, optimally oriented & tilted produces approximately six times more energy than ClearVue under the same conditions per m2 … BUT you can’t see through a silicon cell and it does not form part of the structure.

In the future “smart cities” that are predicted to be built during this decade, it is logical to expect that dozens of “smart buildings” capable of on-site façade-based energy generation will be constructed. Even though each building might harvest between 1 and 5 MWh of energy each sunny day, dozens of interconnected smart buildings will then be able to share their energy on-demand, preventing at least the worst of possible blackout effects in vital infrastructure objects eg. hospitals.

These city-scale distributed generation networks will harvest dozens of MWh each day per suburb, potentially replacing the need for building conventional solar farms and lossy long-range transmission cables in areas outside of CBD zones. A world of opportunities also exists for the engineering of various new device types, both façade-integrated and designed for use inside buildings, from self-powered blinds and building climate control sensors, to internet routers, security cameras and sensors, wireless chargers, and the Internet of Things (IoT) applications.

Double glazed

Similarly to conventional double-glazed low-e windows, the heating and cooling energy costs savings are near 40%, compared to using single-pane windows.

Triple glazed

About double the amount of energy generated per year is saved through superior thermal insulation property of ClearVue window products.

Quadruple glazed

Even better thermal insulation and energy savings, compared to triple-glazed systems.

Vacuum glazed

Vacuum glazed windows reduce the thermal insulation U-factor to well below 1 W/(m2*K), the range not accessible with alternative technologies. Vacuum gaps are typically about 1mm wide, will not reduce power generation, and lead to the ultimate performance in thermal energy savings.

Not including framing or installation and dependent on many factors, such as order size & Insulated Glass Unit (IGU) configuration, approximately US$400 per m2 for a triple glazed low-e IGU.

We suggest you do your own search in your own country (every country is different) but by way of example:

Measurements at different light levels completed by CENER (Spain), 2019

Yes.  During the UL and TUV-SUD certification process, comprehensive third-party certified laboratory product testing was completed.

All lab measurements were performed at standard test conditions (STC, cell temperature 25C, input 1000W/m² at normal incidence)

An approximate assessment of the costs and benefits associated with different glass types is based on web search data and the evaluations of the thermal energy saving performance.

Useful economic calculations can be made with the online calculator available at https://www.efficientwindows.org/new_selection1.php Example data generated for Pittsburgh clearly shows the value of installing quality triple-glazed windows.

The following maximum parameters were measured during the field testing of Murdoch University Greenhouse samples from the roof of Grow Room 3 (windows of dimensions 1.1m x 1.2m):

Isc = 0.98 A; Voc = 61 V, at the ambient temperature above 30C and at solar cells temperature above 40C.

These measured data show that the power outputs measured in field conditions were in excess of 30 Wp/m², in windows with adjusted interlayer composition compared to systems made in 2019.

(Pmax = Isc * Voc * FF, where the Fill Factor (FF) was above 0.75; Pmax > 33 W/m²).

Measured at oblique light incidence angles.

Measurements completed by TUV-SUD (China), 2019

All lab measurements were performed at standard test conditions (STC, cell temperature 25C, input 1000W/m² at normal incidence)